This invention relates in general to lubricant seals and in particular to an improved structure for an annular lubricant seal assembly for providing a seal between a shaft extending through a bore formed in a housing and the housing, wherein the shaft and the housing are rotatable relative to one another.
Annular lubricant seal assemblies are typically used in vehicle axle assemblies for providing a seal between a non-rotating axle spindle or shaft and a rotatable wheel hub or housing disposed about the shaft. Lubricant seal assemblies of this type are provided to both to retain lubricant within the wheel hub and to prevent dirt and other contaminants from entering therein. Known lubricant seal assemblies typically include an annular metallic outer case which is press fit within a bore formed in the wheel hub. An annular inner case is mounted concentrically within the outer case. The axle spindle extends through the inner case, which is free to rotate therewith relative to the outer case. A sealing element formed of a resilent material is typically disposed between the outer case and the inner case. This sealing element includes one or more flexible lips which prevent the escape of lubricant from the housing. The sealing element may also include a supplemental flexible lip to prevent contaminants from entering within the wheel hub.
During operation of the vehicle, the wheel hub not only rotates relative to the axle spindle, but also frequently moves both axially and radially relative thereto. Such axial and radial movement can undesirably distort the shape of the sealing element, resulting in a loss of the seal formed by the flexible lips. Also, repetitious axial and radial movements over a period of time can damage the flexible lips. As a result, lubricant may escape from the wheel hub, and dirt and other contaminants may enter therein. Thus, it would be desirable to provide an improved structure for an annular lubricant seal assembly which can accommodate such relative axial and radial movements, while providing a reliable seal between relatively rotatable components.